In 1940, a deserted airfield somewhere in the heart of England becomes a bustling bomber command station. In 1942 advance units of the American Air Force arrive to join The Royal Air Force and help turn the tide of World War II. So unfolds the story of a group of flyers and their 'missions'.

Peter Penrose (John Mills), a young RAF pilot is sent to Halfpenny Field, close to the small town of Shepley. His Squadron Leader, Flight Lieutenant David Archdale (Michael Redgrave) gives him inspiration and encouragement and they fast become friends. They are joined by a young American pilot Johnny (Douglas Montgomery) which complicates the friendship. This is the story of the group's private lives - particularly their loves during war-time.